The advent of computer networks has proliferated the use of distributed-computing environments. A distributed-computing environment is a type of computing wherein several computer platforms, i.e., different computers, coupled by a network, perform separate but related tasks, (called a process), that are directed in concert toward a single achievement. One example of such a process is the retrieval of all files in a network having the same pattern of letters in the file name. By taking advantage of the computing power of several computers at once, tasks require less time for completion. Use of a processor close to resources to be processed reduces total computing resource requirements.
One method known in the art for practicing a distributed-computing environment is called “remote programming.” In remote programming, a first executing program, called a client process, executing on a first computer system, sends to a second process, called a server process executing on the second computer system, a list of instructions. The instructions are then carried out on the second computer system by the server process, effectuating the goal of the client process. The instructions which the server process is designed to carry out must have some degree of generality, i.e., the instructions must allow some degree of local decision-making with respect to details.
Additionally, object-oriented programming has become one of many familiar models designers and programmers utilize to implement functionality within computer systems. The object model generally is defined by a class structure that includes class members providing both methods and associated data elements belonging to the class. The class members thus provide/define desired functionality within a computer program, wherein an object is declared as an instance of a particular class. As is commonplace, objects often must exchange data and/or invoke other objects operating on the same platform and/or communicate with objects belonging to remote platforms. In order to communicate between objects, interface systems and standards have been developed to define how objects may communicate and/or interact with one another.
There exist systems based on principles of remote and/or object oriented programming that utilize processes called mobile agents (sometimes referred to as mobile objects or agent objects). Such a system may provide the ability for an object (the mobile agent object), existing on a first (“host”) computer system, to transplant itself to a second (“remote host”) computer system while preserving its current execution state. The operation of a mobile agent object is described briefly below.
The instructions of the mobile agent object, its preserved execution state, and other objects owned by the mobile agent object are packaged, or “encoded”, to generate a string of data that is configured so that the string of data can be transported by all standard means of communication over a computer network. Once transported to the remote host, the string of data is decoded to generate a computer process, still called the mobile agent object, within the remote host system. The decoded mobile agent object includes those objects encoded as described above and remains in its preserved execution state. The remote host computer system resumes execution of the mobile agent object which is now operating in the remote host environment.
While now operating in the new environment, the instructions of the mobile agent object are executed by the remote host to perform operations including extracting, defining, creating, and manipulating data objects and interacting with other remote host computer objects. Such operations are often called services.
One problem associated with systems that host mobile objects results from the requirement that such objects have knowledge of the particular characteristics of the host system in order to receive services. If the host system's characteristics should change, the mobile object's knowledge becomes useless. For example, in some prior-art systems, a mobile object, in order to receive a particular service from a host system, must have a priori knowledge of register addresses associated with such service. If these addresses should ever change (as is commonly the case), the mobile object must be reconfigured to receive the service.
Other problems with the prior art not described above can also be overcome using the teachings of embodiments of the present invention, as would be readily apparent to one of ordinary skill in the art after reading this disclosure.